Conventionally, a liquid crystal panel used for a liquid crystal display device is composed of a liquid crystal layer held between a pair of glass substrates, and one of the glass substrates is configured as an active matrix substrate having pixel electrodes. The active matrix substrate has a structure in which gate lines and signal lines are disposed in a grid pattern on the active matrix substrate and switching elements such as TFTs are provided at the intersections of the gate lines and signal lines. A pixel electrode disposed in a region enclosed by the gate lines and the signal lines constitutes a pixel which is a unit of display. In recent years, in order to stabilize a voltage applied to the liquid crystal material, a capacitance wire that forms a capacitance between the pixel electrode and itself is disposed in parallel with the gate wire.
One problem with the liquid crystal panel configured as described above is that when a signal wire breaks at a point, for example, data signal cannot be supplied beyond that point, which significantly lowers the display quality. Technologies disclosed in Patent Documents 1 and 2 are known examples of the solution for this problem.
According to the configuration described in Patent Document 1, a back-up wire is disposed parallel to the signal wire and overlaps the signal wire over the entire length through an insulating layer therebetween. With the auxiliary wire in place, a breakage in a signal wire is repaired by irradiating the signal wire and the back-up wire with a laser and short-circuiting them.
According to the Patent Document 1, back-up wires must be separately provided in addition to other wires. On the other hand, Patent Document 2 discloses a structure in which branch wire branches off from the capacitance wire and is arranged parallel to the signal wire. Part of the branch wire overlaps the signal wire through an insulating layer disposed therebetween. With this configuration, when a signal wire breaks, the branch wire is cut off from the capacitance wire and the portion that overlaps with the signal wire is short-circuited. That is, the branch wire is used as a bypass for the signal wire. In other words, according to Patent Document 2, broken signal wires are repaired by utilizing the branch wires that are a part of the existing structure.